Registration of a fiducial marker for an augmented reality system

Abstract

A registration marker comprising a radiotransparent substrate and a pattern formed in at least two dimensions, which is disposed on the substrate and is optically visible. The registration marker also has a multiplicity of radiopaque elements, which are disposed in the substrate and are spatially arranged in at least two dimensions to provide a unique pattern.

What is claimed is: 
     
       1. A method of manufacturing a registration marker, the method comprising:
 providing a radiotransparent substrate; 
 disposing an optically visible pattern formed in at least two dimensions on the radiotransparent substrate; and 
 disposing in the radiotransparent substrate a multiplicity of radiopaque elements, the radiopaque elements being spatially arranged in at least two dimensions to provide a radiopaque pattern that provides a position and frame of reference of the registration marker, 
 wherein the radiotransparent substrate is optically opaque and comprises a surface, and wherein the optically visible pattern is disposed on the surface, 
 wherein the optically visible pattern comprises optically reflective discrete elements fixedly mounted on the surface, and 
 wherein the optically reflective discrete elements are different from the radiopaque elements. 
 
     
     
       2. The method according to  claim 1 , wherein the optically visible pattern has no axis of symmetry and no plane of symmetry. 
     
     
       3. The method according to  claim 1 , wherein the radiotransparent substrate comprises a pillar attached to a rectangular parallelepiped, and wherein one of the optically reflective discrete elements is mounted on the pillar. 
     
     
       4. The method according to  claim 1 , wherein the radiotransparent substrate comprises an indentation formed within a rectangular parallelepiped, and wherein one of the optically reflective discrete elements is mounted on a surface of the indentation. 
     
     
       5. The method according to  claim 1 , wherein the optically visible pattern is formed in two dimensions. 
     
     
       6. The method according to  claim 1 , wherein the optically visible pattern is formed in three dimensions. 
     
     
       7. The method according to  claim 1 , wherein the radiopaque elements are spatially arranged in two dimensions. 
     
     
       8. The method according to  claim 1 , wherein the radiopaque elements are spatially arranged in three dimensions. 
     
     
       9. The method according to  claim 8 , wherein the radiopaque elements comprise spheres. 
     
     
       10. The method according to  claim 1 , wherein the radiopaque pattern has no axis of symmetry and no plane of symmetry. 
     
     
       11. The method according to  claim 1 , wherein the optically reflective discrete elements comprise discs. 
     
     
       12. A method of manufacturing a registration marker, the method comprising:
 disposing a plurality of optically reflective, radiotransparent, discrete elements in at least two dimensions on a radiotransparent substrate to form an optical pattern for the registration marker; and 
 disposing in the radiotransparent substrate a plurality of radiopaque elements, the radiopaque elements being spatially arranged in at least two dimensions to provide a radiopaque pattern that provides a position and frame of reference of the registration marker 
 wherein the plurality of optically reflective, radiotransparent, discrete elements are different from the plurality of radiopaque elements. 
 
     
     
       13. The method of  claim 12 , wherein disposing the plurality of optically reflective, radiotransparent, discrete elements in at least two dimensions on the radiotransparent substrate comprises fixedly mounting the plurality of optically reflective, radiotransparent, discrete elements on the radiotransparent substrate. 
     
     
       14. The method of  claim 12 , wherein the plurality of optically reflective, radiotransparent, discrete elements comprise discs. 
     
     
       15. The method of  claim 12 , wherein the optical pattern is formed in three dimensions. 
     
     
       16. The method of  claim 15 , wherein the optical pattern has no axis of symmetry and no plane of symmetry. 
     
     
       17. The method of  claim 12 , wherein the plurality of radiopaque elements are spatially arranged in three dimensions. 
     
     
       18. The method of  claim 17 , wherein the radiopaque pattern has no axis of symmetry and no plane of symmetry.